public class swim {
    public static void main(String[] args) {
        useStringHandler((int a,int b)->{System.out.println("a和b 相加的答案是");
        return a+b;
        });
    }



    public static void useStringHandler(StringHandler stringHandler){
       int sum=stringHandler.printMessage(2,5);
        System.out.println(sum);
    }
}


interface StringHandler{
         int printMessage(int a,int b);
}

